let a = String.fromCodePoint(0x78, 0x1f680, 0x79)//String.fromCodePoint方法有多个参数，则它们会被合并成一个字符串返回。
console.log(a);

let b = String.raw`Hi\u000A!`
console.log('---b', b);

let c = String.raw`Hi\\n`
console.log('----c', c);

let s1 = '𠮷a'; //将“𠮷a”视为三个字符
s1.codePointAt(0) // 134071>0xFFFF
s1.codePointAt(1) // 572710>0xFFFF

s1.codePointAt(2) // 97  返回了十进制码点

console.log(s1.codePointAt(0).toString(16)) // "20bb7"
console.log(s1.codePointAt(1).toString(16))//'dfb7'
console.log(s1.codePointAt(2).toString(16))// "61"返回的是十六进制

let s2 = '𠮷a';
console.log(s2.length, '--s2');
for (let ch of s2) {
    console.log(ch.codePointAt(0).toString(16));
}

let arr = [...'𠮷a'];
console.log(arr);//[ '𠮷', 'a' ]
// 20bb7 只返回了‘𠮷’的前两个字节
// 61